This application pertains to the art of couplings and, more particularly, to couplings of the so-called quick connect type. The invention is especially related to coupling of fluid conduits and will be described with particular reference thereto. However, it will be appreciated that the invention has broader aspects and may be used for coupling other conduits and cables or the like.
Quick connect couplings are commonly used in panel board installations where a plurality of different fluid lines are to be connected with several different devices. For example, pressure lines may run from a particular machine to a panel board for connection by quick connect couplings to a series of measuring devices. Hospitals using various gases including oxygen and anesthetic also use quick connect couplings for feeding the gas to a particular type of equipment.
In systems of the type described, care must be exercised to be sure that the proper source of fluid is connected with the proper piece of equipment. Otherwise, damage to the equipment or serious injury to a person may result. In order to alleviate this problem, various color codes, labels and non-interchangeable quick connect couplings have been used. One known type of keyed or coded quick connect system is disclosed in U.S. Pat. No. 3,170,667 issued Feb. 23, 1965, to Szohatzky. In the Szohatzky arrangement, a male member carries a male coupling part having an elongated axially extending cylindrical projection. The female member carries a coupling part having an axially extending recess for receiving the projection when the male and female members are interfitted. A system of couplings is coded by having projections and recesses of varying diameters or radial thicknesses so that each coupling part of a mating pair will not mate with other coupling parts because the projections and recesses will not fit together.
The Szohatzky coupling is arranged so that a coded male or female coupling part will respectively couple with a standard non-coded female or male coupling part. This type of arrangement has been found to be undesirable because coupling of standard coupling parts with coded coupling parts presents potential health hazards and may damage delicate equipment if improper connections are made.
In the Szohatzky coupling, the female coupling part having the recess is essentially a one-piece sleeve. This means that the terminal ends of the sleeve on radially outer and inner sides of the recess openings are always located in the same relative axial position. Furthermore, the axially extending projection on the male coupling part is located intermediate the inner and outer surfaces of that part.
In arranging coded coupling systems, it is desirable to use standard interfitting male and female members. When placing the coded male and female coupling parts of the type disclosed in the Szohatzky patent on standard male and female members, careful tolerance requirements must be maintained in order to achieve a coded coupling system wherein the coded coupling parts will not couple with non-mating coded coupling parts or with non-coded standard coupling parts.